Long-Term Debt - Credit Agreement (Details)			3 Months Ended					12 Months Ended
Long-Term Debt - Credit Agreement (Details)	Jun. 06, 2023 USD ($)	Feb. 24, 2023	Jan. 26, 2025 USD ($)	Oct. 29, 2023 USD ($)	Apr. 30, 2023 USD ($)	Jan. 29, 2023 USD ($)	Apr. 26, 2020 USD ($)	Jan. 25, 2026 USD ($)	Jan. 26, 2025 USD ($)	Jan. 28, 2024 USD ($)	Oct. 26, 2025	Apr. 24, 2025 USD ($)	Jan. 12, 2023 USD ($)	Nov. 07, 2019 USD ($)
Line of Credit Facility [Line Items]
Borrowings under line of credit								$ 0	$ 68,250,000	$ 70,000,000
Repayment of revolving line of credit								0	283,250,000	5,000,000
Repayments of term loans								181,200,000	441,400,000
Outstanding balance			$ 562,662,000					503,000,000	562,662,000
Write-off of deferred financing costs								2,388,000	13,246,000	4,446,000
Proceeds from interest rate swap termination								295,000	4,776,000	0
Interest rate swap termination								1,145,000	$ 3,579,000	$ 0
Interest Rate Swap
Line of Credit Facility [Line Items]
Derivative term							3 years
Triggering Event Two
Line of Credit Facility [Line Items]
Derivative fixed rate			3.58%		3.58%	3.44%			3.58%
LIBOR portion of fixed rate							0.73%
Triggering Event Three
Line of Credit Facility [Line Items]
Derivative fixed rate			4.36%						4.36%
Revolving loans
Line of Credit Facility [Line Items]
Basis spread on variable rate									3.85%
Undrawn revolving commitments								451,600,000
Revolving loans \| Credit Agreement
Line of Credit Facility [Line Items]
Facilities, maximum borrowing capacity												$ 455,000,000.0	$ 600,000,000.0
Repayment of revolving line of credit									$ 215,000,000.0
Outstanding balance								0
Maximum borrowing capacity														$ 75,000,000.0
Basis spread on variable rate		2.50%
Minimum consolidated liquidity	$ 150,000,000
Reduction in borrowing capacity	$ 100,000,000.0
Annual amortization	7.50%
Number of days before maturity date if not extended	91
Debt Instrument, Covenant, Non-Extended Notes And Certain Replacement Debt, Threshold	$ 50,000,000
Decrease in maximum borrowing capacity	$ 100,000,000
Line Of Credit Facility, Increase In Capacity												$ 117,500,000
Revolving loans \| Credit Agreement \| Triggering Event Three
Line of Credit Facility [Line Items]
Leverage ratio maximum	8.17
Minimum liquidity ratio requirement	1.66
Revolving loans \| Credit Agreement \| Triggering Event Four
Line of Credit Facility [Line Items]
Leverage ratio maximum	10.27
Minimum liquidity ratio requirement	1.40
Revolving loans \| Credit Agreement \| Triggering Event Five
Line of Credit Facility [Line Items]
Leverage ratio maximum	10.21
Minimum liquidity ratio requirement	1.37
Revolving loans \| Credit Agreement \| Triggering Event Six
Line of Credit Facility [Line Items]
Leverage ratio maximum	9.93
Minimum liquidity ratio requirement	1.41
Revolving loans \| Credit Agreement \| Triggering Event Seven
Line of Credit Facility [Line Items]
Leverage ratio maximum	8.42
Minimum liquidity ratio requirement	1.73
Revolving loans \| Credit Agreement \| Triggering Event Eight
Line of Credit Facility [Line Items]
Leverage ratio maximum	7.68
Minimum liquidity ratio requirement	1.90
Revolving loans \| Credit Agreement \| Triggering Event Nine
Line of Credit Facility [Line Items]
Leverage ratio maximum	6.75
Minimum liquidity ratio requirement	2.14
Revolving loans \| Credit Agreement \| Triggering Event Ten
Line of Credit Facility [Line Items]
Leverage ratio maximum	6.28
Minimum liquidity ratio requirement	2.37
Revolving loans \| Credit Agreement \| Triggering Event Twelve
Line of Credit Facility [Line Items]
Leverage ratio maximum											4.25
Revolving loans \| Credit Agreement \| Triggering Event Eleven
Line of Credit Facility [Line Items]
Leverage ratio maximum											3.75
Minimum liquidity ratio requirement											3.50
Revolving loans \| Credit Agreement \| Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate		1.50%
Revolving loans \| Credit Agreement \| Secured Overnight Financing Rate (SOFR) \| Debt Instrument, One Month Interest Period
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.11%
Revolving loans \| Credit Agreement \| Secured Overnight Financing Rate (SOFR) \| Debt Instrument, Three Month Interest Period
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.26%
Revolving loans \| Credit Agreement \| Secured Overnight Financing Rate (SOFR) \| Debt Instrument, Six Month Interest Period
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.43%
Revolving loans \| Credit Agreement \| Minimum \| Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.25%
Revolving loans \| Credit Agreement \| Minimum \| Secured Overnight Financing Rate (SOFR)
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.25%
Revolving loans \| Credit Agreement \| Maximum \| Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	2.75%
Revolving loans \| Credit Agreement \| Maximum \| Secured Overnight Financing Rate (SOFR)
Line of Credit Facility [Line Items]
Basis spread on variable rate	3.75%
Revolving loans \| Credit Agreement \| Line of Credit
Line of Credit Facility [Line Items]
Debt hedged by interest rate derivatives							$ 150,000,000.0
Revolving loans \| Credit Agreement, Matures On January 12, 2028
Line of Credit Facility [Line Items]
Facilities, maximum borrowing capacity													405,000,000.0
Revolving loans \| Credit Agreement, Financial Covenant Relief Period \| Minimum \| Base Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate	2.25%
Revolving loans \| Credit Agreement, Financial Covenant Relief Period \| Minimum \| Secured Overnight Financing Rate (SOFR)
Line of Credit Facility [Line Items]
Basis spread on variable rate	3.25%
Term loans \| Credit Agreement \| Line of Credit
Line of Credit Facility [Line Items]
Face amount													$ 895,000,000.0
Outstanding balance			$ 181,212,000					$ 0	181,212,000
Basis spread on variable rate	0.10%
Debt prepayment				$ 250,000,000.0
Derivative term					2 years 9 months	5 years
Debt hedged by interest rate derivatives			150,000,000.0		$ 150,000,000.0	$ 450,000,000.0			$ 150,000,000.0
Proceeds from interest rate swap termination			4,800,000
Interest rate swap termination			$ 3,600,000
Term loans \| Credit Agreement \| Line of Credit \| Triggering Event Two
Line of Credit Facility [Line Items]
Quarterly amortization percentage	1.875%
Term loans \| Credit Agreement \| Line of Credit \| Triggering Event One
Line of Credit Facility [Line Items]
Quarterly amortization percentage	1.25%
Letter of Credit \| Credit Agreement
Line of Credit Facility [Line Items]
Facilities, maximum borrowing capacity														40,000,000.0
Bridge Loan \| Credit Agreement
Line of Credit Facility [Line Items]
Facilities, maximum borrowing capacity														$ 25,000,000.0

SEMTECH CORP 10-K